SourceMgrDiagnosticVerifier.h

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//===- SourceMgrDiagnosticVerifier.h ---------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines a utility for verifying that diagnostics reported through
// a SourceMgr match 'expected-<kind>' comments in the source, for
// implementing '-verify'-style diagnostic tests on top of a plain
// llvm::SourceMgr.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_SUPPORT_SOURCEMGRDIAGNOSTICVERIFIER_H
#define LLVM_SUPPORT_SOURCEMGRDIAGNOSTICVERIFIER_H
 
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Regex.h"
#include "llvm/Support/SourceMgr.h"
#include <optional>
 
namespace llvm {
 
class MemoryBuffer;
class raw_ostream;
 
/// Scans SourceMgr source buffers for 'expected-<kind>' comments (e.g.
/// 'expected-error {{message}}') and verifies that the diagnostics reported
/// to it via \c process match them, and that every expected diagnostic is
/// matched at least once.
class LLVM_ABI SourceMgrDiagnosticVerifier {
public:
  /// The result of matching a single actual diagnostic against the expected
  /// diagnostics recorded for its location.
  enum class MatchResult {
    /// The diagnostic matched an expected diagnostic (kind and text).
    Matched,
    /// The diagnostic's text matched an expected diagnostic, but its kind
    /// didn't; a message about this has already been printed.
    NearMiss,
    /// The diagnostic did not match any expected diagnostic. The caller is
    /// responsible for reporting it, if desired.
    Unexpected,
    /// The diagnostic did not match, but \p reportUnexpected was false, so
    /// nothing was printed and nothing needs to be done.
    Ignored,
  };
 
  /// A single diagnostic expected via an 'expected-<kind>' comment.
  struct ExpectedDiag {
    ExpectedDiag(SourceMgr::DiagKind kind, unsigned lineNo, SMLoc fileLoc,
                 StringRef substring)
        : kind(kind), lineNo(lineNo), fileLoc(fileLoc), substring(substring) {}
 
    /// Returns true if this diagnostic matches the given message.
    LLVM_ABI bool match(StringRef str) const;
 
    /// Computes the regex matcher for a '-re' diagnostic's substring.
    /// Returns false and prints a message through \p mgr on error.
    LLVM_ABI bool computeRegex(raw_ostream &os, SourceMgr &mgr);
 
    /// Prints \p msg at this diagnostic's location and returns false, for
    /// use as `return emitError(...);` in functions that report failure via
    /// a bool return.
    LLVM_ABI bool emitError(raw_ostream &os, SourceMgr &mgr,
                            const Twine &msg) const;
 
    /// The severity of the diagnostic expected.
    SourceMgr::DiagKind kind;
    /// The line number the expected diagnostic should be on.
    unsigned lineNo;
    /// The location of the expected diagnostic within the input file.
    SMLoc fileLoc;
    /// A flag indicating if the expected diagnostic has been matched yet.
    bool matched = false;
    /// The substring that is expected to be within the diagnostic.
    StringRef substring;
    /// An optional regex matcher, if the expected diagnostic substring was a
    /// regex string.
    std::optional<Regex> substringRegex;
  };
 
  /// Recognizes directives starting with any of \p prefixes (e.g.
  /// 'expected-error').
  explicit SourceMgrDiagnosticVerifier(ArrayRef<StringRef> prefixes = {
                                           "expected"});
 
  /// Computes and caches the list of expected diagnostics for \p buf, if not
  /// already cached. Returns the (mutable) cached list.
  MutableArrayRef<ExpectedDiag> computeExpectedDiags(raw_ostream &os,
                                                     SourceMgr &mgr,
                                                     const MemoryBuffer *buf);
 
  /// Returns the cached expected diagnostics for the buffer named \p bufName,
  /// or std::nullopt if \p computeExpectedDiags hasn't been called for it.
  std::optional<MutableArrayRef<ExpectedDiag>>
  getExpectedDiags(StringRef bufName);
 
  /// Returns the expected diagnostics with an '@unknown' location.
  MutableArrayRef<ExpectedDiag> getExpectedUnknownLocDiags() {
    return expectedUnknownLocDiags;
  }
 
  /// Matches a single actual diagnostic against the expected diagnostics
  /// recorded for \p buf / \p lineNo, computing them first via \p
  /// computeExpectedDiags if they haven't been already. If \p hasLoc is
  /// false, the diagnostic has no location and is matched against the
  /// '@unknown' list instead (\p buf / \p lineNo are ignored). If \p hasLoc
  /// is true but \p buf is null (e.g. the diagnostic's file isn't a known
  /// buffer), the diagnostic is matched against an empty list, i.e. it can
  /// never match and is always unexpected. On a near miss, prints a message
  /// through \p mgr. \p reportUnexpected controls whether near misses /
  /// unexpected diagnostics are reported at all.
  MatchResult process(raw_ostream &os, SourceMgr &mgr, SourceMgr::DiagKind kind,
                      bool hasLoc, const MemoryBuffer *buf, unsigned lineNo,
                      StringRef message, bool reportUnexpected = true);
 
  /// Reports (through \p mgr) any expected diagnostic that was never matched
  /// by a call to \p process. Returns whether verification succeeded overall,
  /// i.e. no diagnostic mismatches were recorded either here or by \p
  /// process.
  bool verify(raw_ostream &os, SourceMgr &mgr);
 
private:
  /// Regex used to recognize '<prefix>-<kind>' comments.
  Regex expected;
 
  /// The expected diagnostics for each buffer that has been scanned so far,
  /// keyed by buffer identifier (i.e. file name).
  StringMap<SmallVector<ExpectedDiag, 2>> expectedDiagsPerFile;
 
  /// The expected diagnostics with an '@unknown' location.
  SmallVector<ExpectedDiag, 2> expectedUnknownLocDiags;
 
  /// Whether any diagnostic mismatch has been recorded so far.
  bool ok = true;
};
 
} // namespace llvm
 
#endif // LLVM_SUPPORT_SOURCEMGRDIAGNOSTICVERIFIER_H